Synthesis and impact properties of in situ bulk made ABS resins toughened by high cis-1,4 polybutadiene

In situ bulk polymerization process was employed for the synthesis of poly(acrylonitrile–butadiene–styrene) (ABS) resin. Butadiene (Bd) prepolymer solution was obtained through selective polymerization of Bd in styrene (St) catalyzed by Nd(P507)3/Al(i-Bu)2H/Et3Al2Cl3 catalyst. The catalyst exhibited high activity and selectivity towards the Bd polymerization. The Bd prepolymer yield was higher than 95%. Determined by IR and 1H NMR spectra, the prepolymer had high cis-1,4 stereoregularity (ca. 96%) and low St content (<3.0%). The resultant polymer solution was directly subjected to free radical copolymerization of acrylonitrile and St to provide ABS. The mechanical properties of the ABS resins were as following: impact strength, 42.2–335.9 J m−1; tensile strength, 31.9–44.4 MPa; elongation at break, 20.1–47.6%. The impact strength increased with the increase of polybutadiene content. The ABS toughened by prepolymer with broad Mw/Mn showed higher impact strength than that having narrow Mw/Mn did. Three kinds of initiators, monofunctional BPO, bifunctional DP275B, and trifunctional TETMTPA were examined for the synthesis of ABS. Among them, ABS obtained with DP275B at Bd prepolymer content of 10 wt% displayed the highest impact strength, whose value reached 335.9 J m−1.